System of distribution



March 24, 1925. w 1,530,943 v A. w. HULL SYSTEM OF- DISTRIBUTION 'oiiginal Fil ed Nov. 9, 1921 Magnetic Field InVehtorfl Albert \x/. Hull,

His Attorney.

Patented Mar. 24, 1925.

UNITED STATES.

1 1,530,943 PATENT OFFICE.

ALBERT w. HULL, or SCHENECTADY, NEW YORK, AssIeNon TO GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK.

sYsTEIiI' or DISTRIBUTION.

' Application filed November 9, 1921, Serial No. 513,944. -Renewed October 22, 1924.

[ all whom it may concern:

Be it known that I, ALBERT W. HULL, a citizen of the United States; residing at Schenectady, in the county of Schenectady,

5 State of New York, have invented certain new and useful Improvements in Systems of Distribution, of which the following is a specification. I

The present invention relates to the operation of the magnetically controlled electron discharge device known as the magnetron in combination with a load device subject to short circuit or abnormal load conditions.

As described in the Transactions ofthe American Institute of Electrical Engineers, for September, 1921, the magnetron comprises an evacuated receptacle containing an electron emitting cathode and an anode preferably arranged in circular symmetry with respect to each other, and surrounded by a winding for generating a magnetic field parallel to the cathode. When the field strength increases above.av critical value, the

,electron current is reduced, falling rapidly to zero with a relatively slight increase'of field strength abovethe critical value.

In my prior application, Serial No. 189,- 823, filed August 4, 1921, I have described and claimed a circuit breaker comprising a magnetron arranged to be interc'alated in a circuit to be interrupted, the magnetron thereupon operating to break the current.

The present invention comprises an electric system containing a magnetron continuously operative tocarry the load current and operable automatically to open the load circuit when an abnormal condition occurs such as a short circuit- In the accompanying drawings, Fig. 1 is av diagram of a system embodying my in- 'vention, and Fig. 2 is a graph illustrating electrical characteristics of my device.

Fig. 1 illustrates a direct current system containing a. magnetron which acts automatically without the assistance of external devices to open a circuit in case of an abnormal condition, such as a short circuit, the current-carrying capacity of the magnetron being restored upon the return of normal conditions. My invention may be equally well applied to an alternating current system. In the drawing a magnetron is represented diagrammatically, the envelope be,- ing omitted.

. The cathode 1 and the anode 2 of a magnetron are connected in series with a load device represented by the railway motor having series connected armatures 3 and series windings 4. The -magnetron and motors are connected between a line 5 and ground, asindicated. In the case of an alternating current system two oppositely connected magnetrons are used. The switch 6, in circuit with the cathode heating battery 7, should be closecltorender the cathode incandescent, preferably before the main switch 8 is closed.

Under ordinary conditions the operating voltage across the magnetron terminals is too low to excite the winding 9 sufficiently to prevent normal load current to flow through the device. In case of a short circuit of the load wholly or in part, the voltage across the magnetron terminals rises, and when the voltage exceeds a predetermined value the magnetic field interrupts current flow.

In Fig. 2 I have shown two curves, one curve 10 illustrating the relation of t oltage impressed on the winding to the magnetic field, plotted respectively as ordinates and as abscissae; and the other curve 11 indicating the field value required at. a given voltage to cut. off the current. At voltages up to the voltage E, the magnetic field generatedv by the winding 9 is less than the field value required to prevent current flow. At voltage E the two curves cross, which means that at the voltage E, the magnetic field is suiiicient to interrupt the current. When due to some condition, such as a short circuit in the load, the voltage across the magnetron increases .to a value E, the circuit is interrupted automatically, for at this voltage and at higher voltages the magnetic field prevents the electrons emitted from the cathode from reaching the anode.

lVhat I claim as new and desire to secure by Letters Patent of the United States. is:

1. A system-of distribution comprising a load, an electron discharge device connected in series with said load, and means for decreasing the current-carrying capacity of said electron device when a rise of voltage above a critical value occurs across the terminals of said device.

2. A system of distribution comprising a loa'ddevice, and a magnetron connected. in

' series with said load device, the magnetizing winding of said magnetron constituting a shunt to the main current-carrying path of said magnetron.

3. A system of distribution comprising a load, an electron discharge device containing electrodes having substantially circular symmetry connected in series with said load, magnetic means generating a field substantially parallel to the axis of said device, and electrical connections from said electrode to said magnetic means.

- 4:. A system of distribution comprising a load, an electron discharge device connected in series with said load, and magnetic means for decreasing the current-carrying capacity of said electron device when a rise of voltage above a critical value occurs across the terminals of said device.

5. An electric system of distribution comprising a load, and a magnetron having the main electrodes thereof connected in series with said load, the magnetizing means of said-magnetron being connected to interrupt the current flow between said electrodes when the impressed voltage rises above-a predetermined value.

In witness whereof, I have hereunto set my hand this 7th day of November 1921.

' ALBERT'W; HULL. 

